Controlling oxygen concentration levels during processing of highly-reflective contacts

ABSTRACT

Techniques for controlling oxygen concentration levels during annealing of highly-reflective contacts for LED devices together with lamps, LED device and method embodiments thereto are disclosed.

This application is a continuation of U.S. application Ser. No.15/883,174, filed Jan. 30, 2018, which is a continuation of U.S.application Ser. No. 14/697,390 filed on Apr. 27, 2015, now U.S. Pat.No. 9,917,227, issued Mar. 13, 2018, which claims the benefit under 35U.S.C. § 119(e) to U.S. Provisional Application No. 61/989,693 filed onMay 7, 2014, all of which are incorporated by reference in theirentirety.

FIELD

The disclosure relates to the field of manufacture and use oflight-emitting diodes and more particularly to techniques forcontrolling oxygen concentration levels during processing ofhighly-reflective contacts.

BACKGROUND

In the manufacture of LEDs, especially flip-chip designs, it isadvantageous to produce contacts that are both electrically conductive(to provide current to the device) as well as reflective (to allowphotons to bounce away from the device). Deposition techniques are usedfor the formation of these contacts, and the deposition process is oftenwell controlled for the deposition of high quality metals films.Furthermore, conditions are established and/or controlled so as todeposit materials (e.g., metals) in precise composition and thicknesses.It is known that some metal-semiconductor contacts exhibit highresistance (e.g., after deposition) and some properties of themetal-semiconductor contacts are improved in an annealing step (e.g., toincrease electrical conductivity). Some legacy techniques go to greatlengths to eliminate the presence of oxygen in both the deposition andthe annealing steps (e.g., since oxygen can cause a decrease inreflectivity due to oxidation of the contact material). In some legacycases, a thin layer of Ni or other oxygen gettering material is embeddedin the Ag in the hope that it may reduce the oxidation of the Ag. Theselegacy approaches fail to recognize that oxygen must be present incertain concentrations in order to produce a highly electricallyconductive contact. Moreover, legacy techniques fail to teach how tocontrol the oxygen concentration through the range of processing steps.Additionally, legacy techniques fail to account for desirable effects ofthe presence of oxygen during the processing of metal contacts to allowfor high electrical conductivity.

What is needed is a technique or techniques that allow for precisecontrol of the content (e.g., concentration) of oxygen during theprocessing of the metal contacts in concentrations high enough so as tomaintain high electrical conductivity, yet low enough so as to avoid adecrease in reflectivity due to oxidation of the contacts. Therefore,there is a need for improved approaches.

SUMMARY

Techniques for controlling oxygen concentration levels during processingof highly-reflective contacts are disclosed whereby the followingsystems and methods can be embodied as described in the claims.

Further, aspects of the disclosure include control of oxygen content(e.g., concentrations) and other characteristics of the processingenvironment during the processing of highly conductive contacts (e.g.,onto the p-type gallium- and nitrogen-containing layer) of alight-emitting diode.

BRIEF DESCRIPTION OF THE DRAWINGS

Those skilled in the art will understand that the drawings, describedherein, are for illustration purposes only. The drawings are notintended to limit the scope of the present disclosure.

FIG. 1 is a diagram of a series of semiconductor layers having a stackof metals configured as an electrical contact that has been formed bycontrolling oxygen concentration levels during annealing ofhighly-reflective contacts, according to some embodiments.

FIG. 2 depicts a portion of a process flow for forming an LED device bycontrolling oxygen concentration levels during annealing ofhighly-reflective contacts, according to some embodiments.

FIG. 3A depicts an annealing capsule fitted with fill tubes for formingan LED device by controlling oxygen concentration levels duringannealing of highly-reflective contacts, according to some embodiments.

FIG. 3B depicts a wafer showing device characterization variations afterexperiments for controlling oxygen concentration levels during annealingof highly-reflective contacts, according to some embodiments.

FIG. 4A depicts characterization variation regimes that emerge afterexperiments for controlling oxygen concentration levels during annealingof highly-reflective contacts, according to some embodiments.

FIG. 4B depicts electrical resistivity variations that emerge aftercharacterization of devices formed by varying the conditions andtechniques for controlling oxygen concentration levels during annealingof highly-reflective contacts, according to some embodiments.

FIG. 4C depicts reflectivity variations that emerge aftercharacterization of devices formed by varying the conditions andtechniques for controlling oxygen concentration levels during annealingof highly-reflective contacts, according to some embodiments.

FIG. 4D depicts a chart showing device efficiency, which is a functionof resistance variations and reflectivity variations as exhibited bydevices formed by varying the conditions and techniques for controllingoxygen concentration levels during annealing of highly-reflectivecontacts, according to some embodiments.

FIG. 5A is a secondary ion mass spectroscopy (SIMS) analysis of acontact before annealing.

FIG. 5B is a SIMS scan of a contact after annealing in anoxygen-rarified environment.

FIG. 5C is a SIMS scan of a contact after annealing in an environmentwhere the oxygen concentration is controlled, according to someembodiments.

FIG. 6A exemplifies a process flow for controlling oxygen concentrationlevels during processing steps to form highly-reflective contacts,according to some embodiments.

FIG. 6B exemplifies a process flow for controlling oxygen concentrationlevels during processing steps to form highly-reflective contacts,according to some embodiments.

FIG. 6C shows a flip-chip device having highly-conductive- andhighly-reflective contacts, according to some embodiments.

FIG. 7A through FIG. 7I depict embodiments of the present disclosure inthe form of lamp applications.

FIG. 8A through FIG. 8I depict embodiments of the present disclosureapplied toward lighting applications.

DETAILED DESCRIPTION

The term “exemplary” is used herein to mean serving as an example,instance, or illustration. Any aspect or design described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other aspects or designs. Rather, use of the wordexemplary is intended to present concepts in a concrete fashion.

The term “or” is intended to mean an inclusive “or” rather than anexclusive “or”. That is, unless specified otherwise, or is clear fromthe context, “X employs A or B” is intended to mean any of the naturalinclusive permutations. That is, if X employs A, X employs B, or Xemploys both A and B, then “X employs A or B” is satisfied under any ofthe foregoing instances. In addition, the articles “a” and “an” as usedin this application and the appended claims should generally beconstrued to mean “one or more” unless specified otherwise or is clearfrom the context to be directed to a singular form.

The term “logic” means any combination of software or hardware that isused to implement all or part of the disclosure.

The term “non-transitory computer readable medium” refers to any mediumthat participates in providing instructions to a logic processor.

A “module” includes any mix of any portions of computer memory and anyextent of circuitry including circuitry embodied as a processor.

Reference is now made in detail to certain embodiments. The disclosedembodiments are not intended to be limiting of the claims.

The compositions of matter referred to in the present disclosurecomprise various compositions, some of which are described as follows:

Metal stacks for highly conductive and highly reflective contacts highlyconductive contacts: Strictly as examples, highly conductive contactscan be formed of a stack or sandwich of two or more metal-containingmaterials. highly reflective contacts may contain Ag, Al, Au, Pt, Pd,Ni, Ge, Ti, Ru, or others depending on the wavelength range of thedevice. In some cases, an thin oxygen gettering material is included inthe metal stack and may contain typical oxygen gettering materials suchas Ni, Al, Ti, Mg, Sc, etc.

Solvents: The chemical formulation of solvents used in processing mightcomprise oxygen molecules, and the presence of such oxygen molecules inthe solvents may influence the techniques used for controlling duringprocessing. Strictly as examples, solvent may comprise DMSO, 1165 NMP,Acetone, etc.

The compositions of wavelength-converting materials referred to in thepresent disclosure comprise various wavelength-converting materials.

Wavelength conversion materials can be crystalline (single or poly),ceramic or semiconductor particle phosphors, ceramic or semiconductorplate phosphors, organic or inorganic downconverters, upconverters(anti-stokes), nanoparticles and other materials which providewavelength conversion. Major classes of downconverter phosphors used insolid-state lighting include garnets doped at least with Ce³⁺;nitridosilicates, oxynitridosilicates or oxynitridoaluminosilicatesdoped at least with Ce³⁺; chalcogenides doped at least with Ce³⁻;silicates or fluorosilicates doped at least with Eu ²⁺;nitridosilicates, oxynitridosilicates, oxynitridoaluminosilicates orsialons doped at least with Eu²⁺; carbidonitridosilicates orcarbidooxynitridosilicates doped at least with Eu²⁺; aluminates doped atleast with Eu²⁺; phosphates or apatites doped at least with Eu²⁺;chalcogenides doped at least with Eu²⁺; and oxides, oxyfluorides orcomplex fluorides doped at least with Mn⁴⁺. Some specific examples arelisted below:

(Ba,Sr,Ca,Mg)₅(PO₄)₃(Cl, F,Br,OH):Eu²⁺, Mn²⁺

(Ca,Sr,Ba)₃MgSi₂O₈:Eu²⁺, Mn²⁺

(Ba,Sr,Ca)MgAl₁₀O_(17:)Eu²⁺, Mn²⁺

(Na,K,Rb,Cs)₂[(Si,Ge,Ti,Zr,Hf,Sn)F₆]:Mn⁴⁺

(Mg,Ca,Zr,Ba,Zn)[(Si,Ge,Ti,Zr,Hf,Sn)F₆]:Mn⁴⁺

(Mg,Ca,Sr,Ba,Zn)₂SiO₄:Eu²⁺

(Sr,Ca,Ba)(Al, Ga)₂S₄:Eu²⁺

(Ca,Sr)S:Eu²⁺,Ce³⁺

(Y,Gd,Tb,La,Sm,Pr,Lu)₃(Sc,Al,Ga)₅O₁₂:Ce³⁺

The group:

Ca_(1-x)Al_(x-xy)Si_(1-x+x+y)N_(2-x−xy)C_(xy):A   (1);

Ca_(1-x−z)Na_(z)M(III)_(x-xy−z)Si_(1-x+xy+z)N_(2-x−xy)C_(xy):A   (2);

M(II)_(1-x−z)M(I)_(z)M(III)_(x-xy−z)Si_(1-xy−z)N_(2-x−xy)C_(xy):A   (3);

M(II)_(1-x−z)M(I)_(z)M(III)_(x-xy−z)Si_(1-x+xy+z)N_(2-x−xy−2w/3)C_(xy)O_(w-v/2)H_(v):A  (4); and

M(II)_(1-x-z)M(I)_(z)M(III)_(x-xy−z)Si_(1-x+xy+z)N_(2-x−xy−2w/3−v/3)C_(xy)O_(w)H_(v):A  (4a),

-   -   wherein 0<x<1, 0<y<1, 0z≤1, 0≤v<1, 0<w<1, x+z<1, x>xy+z, and        0<x−xy−z<1, M(II) is at least one divalent cation, M(I) is at        least one monovalent cation, M(III) is at least one trivalent        cation, H is at least one monovalent anion, and A is a        luminescence activator doped in the crystal structure.    -   Ce_(x)(Mg,Ca,        Sr,Ba)_(y)(Sc,Y,La,Gd,Lu)_(1-x−y)Al(Si_(6-z+y)Al(Si_(6-z−y)Al_(z-y))(N_(10-z)O_(z))(where        x,y<1, y≥0 and z˜1)    -   (Mg,Ca,Sr,Ba)(Y,Sc,Gd,Tb,La,Lu)₂S₄:Ce³⁺    -   (Ba,Sr,Ca)_(x)xSi_(y)N_(z):Eu2+(where 2x+4y=3z)    -   (Y,Sc,Lu,Gd)_(2-n)Ca_(n)Si₄N_(6+n)C _(1-n):Ce³⁺, (wherein        0≤n≤0.5)    -   (Lu,Ca,Li,Mg,Y) alpha-SiAlON doped with Eu²⁺ and/or Ce³⁺    -   (Ca,Sr,Ba)SiO₂N₂:Eu²⁺,Ce³⁺    -   (Sr,Ca)AlSiN₃:Eu²⁺    -   CaAlSi(ON)₃:Eu²⁺    -   (Y,La,Lu)Si₃N₅:Ce³⁺    -   (La,Y,Lu)₃Si₆N₁₁:Ce³⁺.

For purposes of the application, it is understood that when a phosphorhas two or more dopant ions (i.e., those ions following the colon in theabove phosphors), this is to mean that the phosphor has at least one(but not necessarily all) of those dopant ions within the material. Thatis, as understood by those skilled in the art, this type of notationmeans that the phosphor can include any or all of those specified ionsas dopants in the formulation. Further, it is to be understood thatnanoparticles, quantum dots, semiconductor particles, and other types ofmaterials can be used as wavelength converting materials. The list aboveis representative and should not be taken to include all the materialsthat may be utilized within embodiments described herein.

Both highly conductive and highly reflective contacts are sought forhigh-power LED chips—including for flip chip designs and GaN-based LEDdesigns—are sought for high-power LEDs. Silver (Ag) is known to have ahigh reflectivity in the visible spectrum. However, as-deposited Agcreates a low conductivity contact. Conventionally-annealed Ag contactsdo not exhibit sufficient conductivity to enable highly-efficient andhigh power operation of GaN LEDs.

Un-oxidized silver has a high reflectivity in the visible spectrummaking Ag the material of choice for contacts and mirrors used incertain LED designs, such as flip chip, that perform better and moreefficiently when the contacts not only provide electricity to the devicebut also act as mirrors. In some situations, Ag contacts can suffer frompoor conductivity and poor adhesion, and known-in-the-art annealingsteps are performed to enhance adhesion and conductivity. However, ifthe annealing step is done in the presence of air or in an environmentthat provides too much oxygen, the Ag contacts will oxidize andreflectivity will be dramatically decreased. To solve these issues,annealing steps can be conducted in a capsule, such as the capsuledescribed in FIG. 3A where air is evacuated with the help of purgegases. Furthermore, it has been observed that pure Ag deposited on GaNhas a tendency to roughen after annealing (e.g., due to uncontrolledgrain growth during the anneal steps). The roughening is not desired asit prevents other metals from being deposited on top of and/orcompromises encapsulation. Even under the best conditions found for theannealing of pure Ag, it has been observed that the resistance exhibitedby the resulting contact will still not be low enough to form ahigh-efficiency light-emitting diode.

Substantial additional experimentation resulted in the discovery thatthe addition of a thin Ni layer embedded in the Ag prevented rougheningafter the annealing step. In experiments involving the addition of thethin Ni layer, the situation depicted in FIG. 3B is observed afterannealing in a set up similar to the one showed in FIG. 3A, with only N₂introduced as a purge gas and where the oxygen was not controlled.Specifically, wafers exhibit some very small-edge regions where thecontacts formed exhibit electrical conductivity within acceptableranges, yet, contacts formed in, or in a close proximity to, the largecentral region exhibit electrical conductivity outside of acceptableranges. Using secondary ion mass spectroscopy (SIMS), it can be verifiedthat the difference between the edge and central region is due to anelevated presence of oxygen where the Ni is present . Some experimentsshow that the O₂ in the edge regions are due to small leaks at the seamsof capsule apparatus that inadvertently introduced oxygen. The SIMSresults are given in FIG. 5A, FIG. 5B, and FIG. 5C. After thisdiscovery, additional experiments were performed so as to determine thedesirable ranges of oxygen, and still further experiments were performedso as to determine how to control oxygen concentrations in the annealingchamber. More specifically, observations from experiments and analysistherefrom result in:

-   Techniques to control gas flow to achieve desirable ranges of oxygen    concentrations,-   Techniques to control oxygen introduced when using solvents,-   Techniques to control oxygen using gettering materials when forming    highly conductive contacts,-   Techniques to control oxygen by interruption of the metal deposition    and intentional or unintentional exposure of the oxygen gettering    layer to oxygen, and-   Techniques to control oxygen by surface treatment of the GaN surface    or by including one or many layers during the growth of the GaN that    result in the release of a controlled amount of oxygen during    subsequent processing.

The treatment of any of the surfaces discussed herein may be subjectedto treatments that result in roughness.

Some of the disclosed techniques include a thin layer of Nickel (Ni) inthe Ag contact to p-GaN (see FIG. 1). The total thickness of the firstAg layer is enough to prevent significant optical loss. In someembodiments, the total thickness of the first Ag layer is about 10 Å orgreater than 100 Å or greater than 1000 Å or greater than 2000 Å. Afterdeposition, the Ag—Ni—Ag stack is annealed. The concentrations of gassesin the annealing chamber, as well as the temperature range and timingsof the anneal processes, were found to be critical. In particular, thecriticality of oxygen concentration levels is discussed infra.

Contacts formed using the hereunder disclosed processes showed excellentoptical and electrical properties, with a specific contact resistance of5E-4 Ohm-cm² or lower. The adhesion of the annealed Ag—Ni—Ag is betterthan that of pure silver (whether annealed or not). The adhesion ofAg—Ni—Ag to the GaN p-type material is sufficient to withstand furtherprocessing. When processed in accordance with the disclosed process, thethin Ni layer serves to control Ag grain growth and further serves toinduce low contact resistance when a certain minimum amount of oxygen ispresent in this layer. Further, the Ag—Ni—Ag stack may be patterned bylift off or etching.

FIG. 1 is a diagram of a series of semiconductor layers 100 used to forma device, the device including a stack of metals configured as anelectrical contact that has been formed by controlling oxygenconcentration levels during processing (e.g., annealing) ofhighly-reflective contacts. The layers comprise a portion of an LED 104,and include an n-type later 114, active region 112, and a p-type layer110, over which is formed a highly conductive contact. The highlyconductive contact is formed of a sandwich or stack of metals (e.g.,contact 102), in this case, a stack comprising a layer of silver 106atop which is a layer of nickel 108 atop which is another layer ofsilver 106. In the specific embodiment shown, the silver layers areabout 1000 Å thick, and the nickel layer is about 5 Å to 20 Å thick. Insome embodiments, the LED growth substrate 115 may include Al₂O₃, SiC,Si, or GaN etc. These substrates may be thinned or removed during theprocessing of the LED. An electrical measurement can be performed on thedevice to ascertain the effectiveness and stability of the oxygen dose(e.g., to measure resistivity of the contact).

FIG. 2 depicts a portion of a process flow 200 for forming an LED deviceby controlling oxygen concentration levels during annealing ofhighly-reflective contacts. Shown is a chart, including several stepsperformed during the formation of an LED on a wafer (see step 204). Atopof the substrate (e.g., substrate of Al,2O₃, SiC, Si, etc.) an n-typelayer is formed. The n-type layer is formed of a semiconducting material(e.g., GaN, doped with Si or O) followed by formation of anepitaxially-grown active region (e.g., using InGaN), atop of which isformed a p-type layer (e.g., GaN doped with Mg) to form the LED. In thedeposition steps (see deposition 206), the three layers of contact 102are formed using a deposition chamber. As shown, the deposition includesdepositing a silver layer (see step 208), depositing a nickel (see step210), and depositing another silver layer (see step 212). The depositedmetals are annealed at a temperature less than the melting point of thedeposited metals where oxygen is controlled (see step 214). In exemplarycases, the annealing causes diffusion of the nickel into the silver,which in turn can blur the transitions from silver to nickel and fromnickel to silver so that the nickel layer might appear (e.g., in a SIMSscan) as thinner than the aforementioned 5 Å to 20 Å. The Ni—Aginterfaces may or may not exhibit sharp transition regions. Afteradditional processing steps, the LEDs on the wafers are singulated (seestep 216) to produce individual devices such as is depicted in thedevice of FIG. 1.

Controlling the atmosphere within the annealing chamber is facilitatedby using fill tubes and evacuation tubes, as are shown and discussed aspertains to FIG. 3A.

FIG. 3A depicts an annealing apparatus 3A00 fitted with fill tubes forforming an LED device by controlling oxygen concentration levels duringannealing of highly-reflective contacts.

As shown in FIG. 3A, the annealing capsule 302 has many interfaces tothe ambient environment (e.g., N₂ fill-tube 308, 02 fill-tube 309,evacuation tube 306). Some apparatus for annealing (e.g., furnace,capsule) have tendencies to leak oxygen into the annealing capsule(e.g., through a seam or seams), and the leaked oxygen comes in contactwith the surfaces of the wafers 304. Some wafers that are processed inan apparatus such as depicted in FIG. 3A exhibit good contacts onlyaround the outer edges of the wafer (e.g., see high conductivitycontacts 314 of FIG. 3B). Contacts formed nearer to the center of thewafer (e.g., in the large inner region 310) exhibit bad contactcharacteristics (e.g., see low conductivity contacts 312 of FIG. 3B).SIMS scans performed on selected contacts (e.g., both selected from theouter periphery and from selected locations nearer to the center of thewafer) exhibit measurable differences as comparing good and badcontacts. In particular, contacts from devices formed in the small outerregion 320 show a higher oxygen concentration in the Ni layer ascompared to contacts formed nearer to the center of the wafer. Contactsfrom devices formed in the small outer region 320 are measured to behighly-conductive (good contacts).

FIG. 3B depicts a wafer showing device characterization variations 3B00after experiments for controlling oxygen concentration levels duringannealing of highly-reflective contacts. The face of a wafer is dividedinto two regions. A first region (see small outer region 320) comprisesdevices that statistically more often exhibit the desiredcharacteristics of high electrical conductivity as well as highreflectivity (e.g., without significant tarnishing). A second region(see large inner region 310) comprises devices that statistically moreoften exhibit the undesirable characteristics of low electricalconductivity. This observation motivated experimentation to identify thecause of the performance variation between the devices taken from theinner region as compared with the performance of devices taken from theouter region. Observations correlated to the concentration of oxygen inthe chamber during the deposition processes. In one set of experiments,substantially all of the oxygen in the chamber was evacuated and theconductivity of the contacts was measured and was found to be low. Inanother set of experiments, a small, controlled amount of oxygen wasflowed into the chamber during annealing, and the conductivity of thecontacts was measured and was found to be high. Further experimentsshowed the measured conductivity over a range from very low oxygenconcentrations to much higher concentrations. Results of the foregoingexperiments (e.g., characterization of the resulting devices) areplotted in the diagrams of FIG. 4A, FIG. 4B, FIG. 4C and FIG. 4D.

FIG. 4A depicts characterization variation regimes 4A00 that emergeafter experiments for controlling oxygen concentration levels duringannealing of highly-reflective contacts.

FIG. 4A depicts four regimes 402 of contact characteristics that arecorrelated to varying concentrations of oxygen. In the leftmost “lowconductivity regime” the contacts exhibit low conductivity 404. As theconcentration of oxygen is increased, the contacts begin to exhibitprogressively higher to high conductivity 406 throughout the desired“mid-range concentration regime”. As the oxygen concentration goes stillhigher, the contacts formed in such relatively high oxygenconcentrations begins to exhibit again a lower conductivity 408. Atstill higher oxygen concentrations, the presence of oxygen during theannealing processes introduces tarnishing of the metals (e.g., silveroxidation 410), which is undesirable for reflectivity.

FIG. 4B and FIG. 4C depict variations in resistivity 412 as oxygenconcentration is increased (see FIG. 4B), and variations in reflectivity414 as oxygen concentration is increased (see FIG. 4C). The variationsof resistivity and reflectivity are superimposed in FIG. 4D. Thevariations of resistivity and reflectivity are now briefly discussed.

FIG. 4B depicts electrical resistivity variations 4B00 that emerge aftercharacterization of devices formed by varying the conditions andtechniques for controlling oxygen concentration levels during annealingof highly-reflective contacts.

FIG. 4C depicts reflectivity variations 4C00 that emerge aftercharacterization of devices formed by varying the conditions andtechniques for controlling oxygen concentration levels during annealingof highly-reflective contacts.

FIG. 4D depicts a chart 4D00 showing device efficiency, which is afunction of resistivity variations and reflectivity variations. Theresistivity variation curve is plotted over a reflectivity variationcurve, and further, a device efficiency curve 413 is superimposed overthe resistivity variation and reflectivity variation curves.

FIG. 5A is a secondary ion mass spectroscopy (SIMS) analysis 5A00 of acontact before annealing. The shown SIMS scan is taken after deposition(and before annealing). This depicts bad (e.g., poorly conducting)contact. Little oxygen is present. As shown, the oxygen concentration502 is less than about 5×10¹⁹cm⁻³). The absolute concentration depends,at least in part, on the Ni thickness in the Ag/Ni/Ag stack. It isvisible that the Ni atoms have not diffused to the semiconductor-metalinterface.

FIG. 5B is a SIMS scan 5B00 of a contact after annealing in anoxygen-rarified environment. The shown SIMS is taken after anneal whennot enough oxygen is provided during the anneal step (the oxygen in theNi layer is similar to as deposited, such as is shown in FIG. 5A). Inthis case the rarified oxygen concentration 504, expressed in atoms pervolume is less than about 5×10¹⁹cm⁻³. It is visible that Ni atoms havediffused through the Ag to the semiconductor-metal interface. This is apoorly conducting contact.

FIG. 5C is a SIMS scan 5C00 of a contact after annealing in anenvironment where the oxygen concentration is controlled to provideenough oxygen during the anneal step. As shown, the Ni layer oxygenconcentration 505 is greatly increased as compared to oxygen in the Nilayer as of the time it was deposited. In the case as shown in the SIMSscan 5C00, the oxygen concentration (in atoms per volume) is in the mid10²⁰ cm⁻³ (from about 1×10²⁰ cm⁻³ to about 7'10²⁰ cm⁻³). The absoluteconcentration may depend on the Ni thickness. This SIMS scan depicts agood (e.g., highly conducting) contact. It is visible that Ni atoms havediffused to the metal-semiconductor interface.

FIG. 6A exemplifies a process flow 6A00 for controlling oxygenconcentration levels during processing steps to form highly-reflectivecontacts. As shown, the processing flow includes steps for liftoff andannealing (see steps 615 ₁). The conditions under which the liftoff andannealing steps are performed serve, either singly or in combination, tocontrol the oxygen atom concentrations that remain in the layers of theresulting contacts.

FIG. 6B exemplifies a process flow 6B00 for controlling oxygenconcentration levels during processing steps to form highly-reflectivecontacts. As shown, the processing flow includes liftoff and annealingsteps 615 ₂ that serve, either singly or in combination, to control theoxygen concentration levels during processing. As shown, the liftoffsteps use oxygen-containing solvents. During annealing, Ni is diffusedinto Ag while the presence of oxygen in the annealing environment iscontrolled.

FIG. 6C shows a flip-chip device 6C00 having a highly-conductive andhighly-reflective n-contact 621. More specifically, the shown devicedepicts an epitaxially-formed LED atop a submount formed of a substrate626 and wiring 624. Solder serves to electrically connect the highlyconductive and highly reflective contact 601 to wiring 624.

As shown, the die is encapsulated. The encapsulant 625 can be loadedwith wavelength-converting materials (e.g., red-emitting phosphor,blue-emitting phosphor, green-emitting phosphor, etc.). In some casesthe encapsulant is also loaded with thermally-conductive materials,which may be index matched. Related techniques are disclosed in U.S.application Ser. No. 14/097,481, filed on Dec. 5, 2013, each of which isincorporated by reference in its entirety.

Given the aforementioned discoveries, an apparatus can be designed so asto precisely control the amount of oxygen in the annealing furnace so asto achieve the desired oxygen concentration (e.g., in the mid-rangeconcentration regime). For example, an annealing furnace can beconfigured to have a flow tube into which a gas (e.g., oxygen, nitrogen)or a mixture of gasses can be introduced. In order to evacuate thechamber of oxygen, another purge gas (e.g., nitrogen gas) can be flowedfor a duration. Certain annealing steps are carried out in the oxygenfree atmosphere within the chamber. Other annealing steps can be carriedout in the presence of a precisely-controlled concentration of oxygen.Such control can be enabled by controlling the pressure and duration ofthe introduction of oxygen into the flow tube.

The aforementioned apparatus is but one possible embodiment. Otherapparatus include vacuum furnaces where the entire annealing chamber isevacuated of gas (e.g., using a vacuum pump). Oxygen and/or nitrogen maybe introduced at any time to control the oxygen present in the oxygengettering layer, according to the herein disclosed techniques.

In various situations, controlling oxygen concentration levels whenforming highly-reflective and electrically conductive contacts of anoptoelectronic semiconductor device can include: (1) depositing ametallic stack on a semiconductor plane of the optoelectronicsemiconductor device (e.g., where the stack comprises a silver layer andan oxygen-gettering metal); and/or (2) introducing a dose of oxygen intothe metallic stack at a varying rate of flow (and/or varying the rate offlow of nitrogen); and/or (3) annealing the optoelectronic semiconductordevice to diffuse an oxygen-gettering metal into the interfaces betweena semiconductor layer and the metallic stack.

The use of the foregoing apparatus and methods results in LEDs thatexhibit the following characteristics:

-   A highly conductive Ag-based contact processed according to the    disclosed techniques can have a contact resistance of 5×10⁻⁴ Ohm-cm²    or lower as can be measured by a transmission line measurement    (TLM).-   The highly conductive Ag-based contacts processed according to the    disclosed techniques are also highly reflective, as can be measured    by reflectance measurements. The measured reflectivity of the    Ag-based contact is at least as high as the reflectivity of Ag    described in Handbook of Optical Constants of Solids by Edward D.    Palik (1985).-   Due to the high reflectivity and the high conductivity of the    Ag-based contact processed according to the disclosed techniques,    the LED made with such a contact may be operated with a high wall    plug efficiency of at least 50% at 200 Å/cm² and 130° C.    -   -   The adhesion of a Ag-based contact to GaN allows for            reliable processing and reliable operation of the LED.        -   The metal stack forming the contact contains oxygen in an            elevated concentration. For example, the nickel layer            contains an elevated oxygen concentration level.        -   The contact can be measured to show a higher oxygen            concentration than was present after deposition and before            annealing where the oxygen-gettering material (such as            Nickel) is present. For example, the higher oxygen            concentration can be in the range of 5×10¹⁹ cm⁻³ or higher            atoms per cubic centimeter.-   The oxygen-gettering material (such as Nickel) has diffused to the    metal-semiconductor interface.

For subsequent metal layers, it was found that platinum (Pt) should notbe in contact with Ag if the LED chip goes through a high temperatureprocess (T>300° C.) as the high temperature process degrades both theelectrical and optical properties of the contact. Thus if subsequentlayers are deposited, an acceptable metal scheme may be Ti—Pt—Au—Pt(1000 Å-1000 Å-5000 Å-1200 Å). Strictly as an example, one possiblemetal scheme was shown to allow for good protection of the Ag contact aswell as a good contact to the AuSn die attach process.

LED devices made in accordance with the foregoing can be used inillumination devices such as lamps such as MR-16 lamps. Theaforementioned MR-16 lamp is merely one embodiment of a lamp thatconforms to fit with any one or more of a set of mechanical andelectrical standards. Table 1 gives standards (see “Designation”) andcorresponding characteristics.

TABLE 1 Base Diameter Desig- (Crest of IEC 60061-1 nation thread) Namestandard sheet E05 05 mm Lilliput Edison Screw (LES) 7004-25 E10 10 mmMiniature Edison Screw (MES) 7004-22 E11 11 mm Mini-Candelabra EdisonScrew (7004-06-1) (mini-can) E12 12 mm Candelabra Edison Screw (CES)7004-28 E14 14 mm Small Edison Screw (SES) 7004-23 E17 17 mmIntermediate Edison Screw (IES) 7004-26 E26 26 mm [Medium] (one-inch)Edison 7004-21A-2 Screw (ES or MES) E27 27 mm [Medium] Edison Screw (ES)7004-21 E29 29 mm [Admedium] Edison Screw (ES) E39 39 mm Single-contact(Mogul) Giant 7004-24-A1 Edison Screw (GES) E40 40 mm (Mogul) GiantEdison Screw 7004-24 (GES)

Additionally, the base member of a lamp can be of any form factorconfigured to support electrical connections, which electricalconnections can conform to any of a set of types or standards. Forexample, Table 2 gives standards (see “Type”) and correspondingcharacteristics, including mechanical spacing between a first pin (e.g.,a power pin) and a second pin (e.g., a ground pin).

TABLE 2 Pin center Type Standard to center Pin Diameter Usage G4 IEC60061-1 4.0 mm 0.65-0.75 mm MR11 and other small halogens of (7004-72)5/10/20 watt and 6/12 volt GU4 IEC 60061-1 4.0 mm 0.95-1.05 mm(7004-108) GY4 IEC 60061-1 4.0 mm 0.65-0.75 mm (7004-72A) GZ4 IEC60061-1 4.0 mm 0.95-1.05 mm (7004-64) G5 IEC 60061-1 5 mm T4 and T5fluorescent tubes (7004-52-5) G5.3 IEC 60061-1 5.33 mm 1.47-1.65 mm(7004-73) G5.3-4.8 IEC 60061-1 (7004-126-1) GU5.3 IEC 60061-1 5.33 mm1.45-1.6 mm (7004-109) GX5.3 IEC 60061-1 5.33 mm 1.45-1.6 mm MR16 andother small halogens of (7004-73A) 20/35/50 watt and 12/24 volt GY5.3IEC 60061-1 5.33 mm (7004-73B) G6.35 IEC 60061-1 6.35 mm 0.95-1.05 mm(7004-59) GX6.35 IEC 60061-1 6.35 mm 0.95-1.05 mm (7004-59) GY6.35 IEC60061-1 6.35 mm 1.2-1.3 mm Halogen 100 W 120 V (7004-59) GZ6.35 IEC60061-1 6.35 mm 0.95-1.05 mm (7004-59A) G8 8.0 mm Halogen 100 W 120 VGY8.6 8.6 mm Halogen 100 W 120 V G9 IEC 60061-1 9.0 mm Halogen 120 V(US)/230 V (EU) (7004-129) G9.5 9.5 mm 3.10-3.25 mm Common for theatreuse, several variants GU10 10 mm Twist-lock 120/230-volt MR16 halogenlighting of 35/50 watt, since mid-2000s G12 12.0 mm 2.35 mm Used intheatre and single-end metal halide lamps G13 12.7 mm T8 and T12fluorescent tubes G23 23 mm 2 mm GU24 24 mm Twist-lock forself-ballasted compact fluorescents, since 2000s G38 38 mm Mostly usedfor high-wattage theatre lamps GX53 53 mm Twist-lock for puck-shapedunder- cabinet compact fluorescents, since 2000s

The list above is representative and should not be taken to include allthe standards or form factors that may be used within embodimentsdescribed herein.

FIG. 7A through FIG. 7I depict embodiments of the present disclosure inthe form of lamp applications. In these lamp applications, one or morelight-emitting diodes are used in lamps and fixtures. Such lamps andfixtures include replacement and/or retro-fit directional lightingfixtures.

In some embodiments, aspects of the present disclosure can be used in anassembly. As shown in FIG. 7A, an assembly can comprise:

-   a screw cap 728-   a driver housing 726-   a driver board 724-   a heat sink 722-   a metal-core printed circuit board 720-   an LED lightsource 718-   a dust shield 716-   a lens 714-   a reflector disc 712-   a magnet 710-   a magnet cap 708-   a trim ring 706-   a first accessory 704-   a second accessory 702

The components of assembly 7A00 may be described in substantial detail.Some components are ‘active components’ and some are ‘passive’components, and can be variously-described based on the particularcomponent's impact to the overall design, and/or impact(s) to theobjective optimization function. A component can be described using aCAD/CAM drawing or model, and the CAD/CAM model can be analyzed so as toextract figures of merit as may pertain to e particular component'simpact to the overall design, and/or impact(s) to the objectiveoptimization function. Strictly as one example, a CAD/CAM model of atrim ring is provided in a model corresponding to the drawing of FIG.7A2.

The components of the assembly 7A00 can be fitted together to form alamp. FIG. 7B depicts a perspective view 730 and top view 732 of such alamp. As shown in FIG. 7B, the lamp 7B00 comports to a form factor knownas PAR30L. The PAR30L form factor is further depicted by the principalviews (e.g., left 740, right 736, back 734, front 738 and top 742) givenin array 7C00 of FIG. 7C.

The components of the assembly 7A00 can be fitted together to form alamp. FIG. 7D depicts a perspective view 744 and top view 746 of such alamp. As shown in FIG. 7D, the lamp 7D00 comports to a form factor knownas PAR30S. The PAR30S form factor is further depicted by the principalviews (e.g., left 754, right 750, back 748, front 752 and top 756) givenin array 7E00 of FIG. 7E.

The components of the assembly 7A00 can be fitted together to form alamp. FIG. 7F depicts a perspective view 758 and top view 760 of such alamp. As shown in FIG. 7F, the lamp 7F00 comports to a form factor knownas PAR38. The PAR38 form factor is further depicted by the principalviews (e.g., left 768, right 764, back 762, front 766 and top 770) givenin array 7G00 of FIG. 7G.

The components of the assembly 7A00 can be fitted together to form alamp. FIG. 7H depicts a perspective view 772 and top view 774 of such alamp. As shown in FIG. 7H, the lamp 7H00 comports to a form factor knownas PAR111. The PAR111 form factor is further depicted by the principalviews (e.g., left 782, right 778, back 776, front 780 and top 784) givenin array 7100 of FIG. 7I.

FIG. 8A through FIG. 8I depict embodiments of the present disclosure ascan be applied toward lighting applications. In these embodiments, oneor more light-emitting diodes 8A10, as taught by this disclosure, can bemounted on a submount or package to provide an electricalinterconnection. The submount or package can be a ceramic, oxide,nitride, semiconductor, metal, or combination thereof that includes anelectrical interconnection capability 8A20 for the various LEDs. Thesubmount or package can be mounted to a heatsink member 8B50 via athermal interface. The LEDs can be configured to produce a desiredemission spectrum, either by mixing primary emissions from various LEDs,or by having the LEDs photo-excite wavelength down-conversion materialssuch as phosphors, semiconductors, or semiconductor nanoparticles(“quantum dots”), or a combination of any of the foregoing.

The total light emitting surface (LES) of the LEDs and anydown-conversion materials can form a light source 8A30. One or morelight sources can be interconnected into an array 8B20, which in turn isin electrical contact with connectors 8B10 and brought into an assembly8B30. One or more lens elements 8B40 can be optically coupled to thelight source. The lens design and properties can be selected so that thedesired directional beam pattern for a lighting product is achieved fora given LES. The directional lighting product may be an LED module, aretrofit lamp 8B70, or a lighting fixture 8C30. In the case of aretrofit lamp, an electronic driver can be provided with a surroundingmember 8B60, the driver to condition electrical power from an externalsource to render it suitable for the LED light source. The driver can beintegrated into the retrofit lamp. In the case of a fixture, anelectronic driver is provided which conditions electrical power from anexternal source to make it suitable for the LED light source, with thedriver either integrated into the fixture or provided externally to thefixture. In the case of a module, an electronic driver can be providedto condition electrical power from an external source to render itsuitable for the LED light source, with the driver either integratedinto the module or provided externally to the module. Examples ofsuitable external power sources include mains AC (e.g., 120 Vrms AC or240 Vrms AC), low-voltage AC (e.g., 12 VAC), and low-voltage DC (e.g.,12 VDC). In the case of retrofit lamps, the entire lighting product maybe designed to fit standard form factors (e.g., ANSI form factors).Examples of retrofit lamp products include LED-based MR16, PAR16, PAR20,PAR30, PAR38, BR30, A19 and various other lamp types. Examples offixtures include replacements for halogen-based and ceramic metalhalide-based directional lighting fixtures.

In some embodiments, the present disclosure can be applied tonon-directional lighting applications. In these embodiments, one or morelight-emitting diodes (LEDs), as taught by the disclosure, can bemounted on a submount or package to provide an electricalinterconnection. The submount or package can be, for example, a ceramic,oxide, nitride, semiconductor, metal, or combination of any of theforegoing that includes electrical interconnection capability for thevarious LEDs. The submount or package can be mounted to a heatsinkmember via a thermal interface. The LEDs can be configured to produce adesired emission spectrum, either by mixing primary emissions fromvarious LEDs, or by having the LEDs photo-excite wavelengthdown-conversion materials such as phosphors, semiconductors, orsemiconductor nanoparticles (“quantum dots”), or a combination thereof.The LEDs can be distributed to provide a desired shape of the lightsource. For example, one common shape is a linear light source forreplacement of conventional fluorescent linear tube lamps. One or moreoptical elements can be coupled to the LEDs to provide a desirednon-directional light distribution. The non-directional lighting productmay be an LED module, a retrofit lamp, or a lighting fixture. In thecase of a retrofit lamp, an electronic driver can be provided tocondition electrical power from an external source to render it suitablefor the LED light source, with the driver integrated into the retrofitlamp. In the case of a fixture, an electronic driver is provided tocondition electrical power from an external source to render it suitablefor the LED light source, with the driver either integrated into thefixture or provided externally to the fixture. In the case of a module,an electronic driver can be provided to condition electrical power froman external source to render it suitable for the LED light source, withthe driver either integrated into the module or provided externally tothe module. Examples of external power sources include mains AC (e.g.,120 Vrms AC or 240 Vrms AC), low-voltage AC (e.g., 12 VAC), andlow-voltage DC (e.g., 12 VDC). In the case of retrofit lamps, the entirelighting product may be designed to fit standard form factors (e.g.,ANSI form factors). Examples of retrofit lamp products include LED-basedreplacements for various linear, circular, or curved fluorescent lamps.An example of a non-directional lighting product is shown in FIG. 8C.Such a lighting fixture can include replacements for fluorescent-basedtroffer luminaires. In this embodiment, LEDs are mechanically securedinto a package 8C10, and multiple packages are arranged into a suitableshape such as linear array 8C20.

Some embodiments of the present disclosure can be applied tobacklighting for flat panel display applications. In these embodiments,one or more light-emitting diodes (LEDs), as taught by this disclosure,can be mounted on a submount or package to provide an electricalinterconnection. The submount or package can be a ceramic, oxide,nitride, semiconductor, metal, or combination of any of the foregoingthat include electrical interconnection capability for the various LEDs.The submount or package can be mounted to a heatsink member via athermal interface. The LEDs can be configured to produce a desiredemission spectrum, either by mixing primary emissions from various LEDs,or by having the LEDs photo-excite wavelength down-conversion materialssuch as phosphors, semiconductors, or semiconductor nanoparticles(“quantum dots”), or a combination of any of the foregoing. The LEDs canbe distributed to provide a desired shape of the light source. Onecommon shape is a linear light source. The light source can be opticallycoupled to a lightguide for the backlight. This can be achieved bycoupling at the edge of the lightguide (edge-lit), or by coupling lightfrom behind the lightguide (direct-lit). The lightguide distributeslight uniformly toward a controllable display such as a liquid crystaldisplay (LCD) panel. The display converts the LED light into desiredimages based on electrical control of light transmission and its color.One way to control the color is by use of filters (e.g., color filtersubstrate 8D40). Alternatively, multiple LEDs may be used and driven inpulsed mode to sequence the desired primary emission colors (e.g., usinga red LED 8D30, a green LED 8D10, and a blue LED 8D20). Optionalbrightness-enhancing films may be included in the backlight “stack”. Thebrightness-enhancing films narrow the flat panel display emission toincrease brightness at the expense of the observer viewing angle. Anelectronic driver can be provided to condition electrical power from anexternal source to render it suitable for the LED light source forbacklighting, including any color sequencing or brightness variation perLED location (e.g., one-dimensional or two-dimensional dimming).Examples of external power sources include mains AC (e.g., 120 Vrms ACor 240 Vrms AC), low-voltage AC (e.g., 12 VAC), and low-voltage DC(e.g., 12 VDC). Examples of backlighting products are shown in FIG. 8D1,FIG. 8D2, FIG. 8E1 and FIG. 8E2.

Some embodiments of the present disclosure can be applied to automotiveforward lighting applications, as shown in FIG. 8F (e.g., see theexample of an automotive forward lighting product 8F30). In theseembodiments, one or more light-emitting diodes (LEDs) can be mounted ona submount or on a rigid or semi-rigid package 8F10 to provide anelectrical interconnection. The submount or package can be a ceramic,oxide, nitride, semiconductor, metal, or combination thereof, thatinclude electrical interconnection capability for the various LEDs. Thesubmount or package can be mounted to a heatsink member via a thermalinterface. The LEDs can be configured to produce a desired emissionspectrum, either by mixing primary emission from various LEDs, or byhaving the LEDs photo-excite wavelength down-conversion materials suchas phosphors, semiconductors, or semiconductor nanoparticles (“quantumdots”), or a combination of any of the foregoing. The total lightemitting surface (LES) of the LEDs and any down-conversion materialsform a light source. One or more lens elements 8F20 can be opticallycoupled to the light source. The lens design and properties can beselected to produce a desired directional beam pattern for an automotiveforward lighting application for a given LED. An electronic driver canbe provided to condition electrical power from an external source torender it suitable for the LED light source. Power sources forautomotive applications include low-voltage DC (e.g., 12 VDC). An LEDlight source may perform a high-beam function, a low-beam function, aside-beam function, or any combination thereof.

In some embodiments the present disclosure can be applied to digitalimaging applications such as illumination for mobile phone and digitalstill cameras (e.g., see FIG. 8G). In these embodiments, one or morelight-emitting diodes (LEDs), as taught by the disclosure, can bemounted on a submount or package 8G10 to provide an electricalinterconnection. The submount or package can be, for example, a ceramic,oxide, nitride, semiconductor, metal, or combination of any of theforegoing, that include electrical interconnection capability for thevarious LEDs. The submount or package can be mounted to a circuit boardmember and fitted with or into a mounting package 8G20. The LEDs can beconfigured to produce a desired emission spectrum, either by mixingprimary emission from various LEDs, or by having the LEDs photo-excitewavelength down-conversion materials such as phosphors, semiconductors,or semiconductor nanoparticles (“quantum dots”), or a combinationthereof. The total light emitting surface (LES) of the LEDs and anydown-conversion materials form a light source. One or more lens elementscan be optically coupled to the light source. The lens design andproperties can be selected so that the desired directional beam patternfor an imaging application is achieved for a given LES. An electronicdriver can be provided to condition electrical power from an externalsource to render it suitable for the LED light source. Examples ofsuitable external power sources for imaging applications includelow-voltage DC (e.g., 5 VDC). An LED light source may perform alow-intensity function 8G30, a high-intensity function 8G40, or anycombination thereof

Some embodiments of the present disclosure can be applied to mobileterminal applications. FIG. 8H is a diagram illustrating a mobileterminal (see smart phone architecture 8H00). As shown, the smart phone8H06 includes a housing, display screen, and interface device, which mayinclude a button, microphone, and/or touch screen. In certainembodiments, a phone has a high resolution camera device, which can beused in various modes. An example of a smart phone can be an iPhone fromApple Inc. of Cupertino, Calif. Alternatively, a smart phone can be aGalaxy from Samsung, or others.

In an example, the smart phone may include one or more of the followingfeatures (which are found in an iPhone 4 from Apple Inc., although therecan be variations), see www.apple.com:

-   GSM model: UMTS/HSDPA/HSUPA (850, 900, 1900, 2100 MHz); GSM/EDGE    (850, 900, 1800, 1900 MHz)-   CDMA model: CDMA EV-DO Rev. A (800, 1900 MHz)-   802.11b/g/n Wi-Fi (802.11n 2.4GHz only)-   Bluetooth 2.1 +EDR wireless technology-   Assisted GPS-   Digital compass-   Wi-Fi-   Cellular-   Retina display-   3.5-inch (diagonal) widescreen multi-touch display-   800:1 contrast ratio (typical)-   500 cd/m2 max brightness (typical)-   Fingerprint-resistant oleophobic coating on front and back-   Support for display of multiple languages and characters    simultaneously-   5-megapixel iSight camera-   Video recording, HD (720p) up to 30 frames per second with audio-   VGA-quality photos and video at up to 30 frames per second with the    front camera-   Tap to focus video or still images-   LED flash-   Photo and video geotagging-   Built-in rechargeable lithium-ion battery-   Charging via USB to computer system or power adapter-   Talk time: Up to 20 hours on 3G, up to 14 hours on 2G (GSM)-   Standby time: Up to 300 hours-   Internet use: Up to 6 hours on 3G, up to 10 hours on Wi-Fi-   Video playback: Up to 10 hours-   Audio playback: Up to 40 hours-   Frequency response: 20 Hz to 22,000 Hz-   Audio formats supported: AAC (8 to 320 Kbps), protected AAC (from    iTunes Store), HE-AAC, MP3 (8 to 320 Kbps), MP3 VBR, audible    (formats 2, 3, 4, audible enhanced audio, AAX, and AAX+), Apple    lossless, AIFF, and WAV-   User-configurable maximum volume limit-   Video out support with Apple digital AV adapter or Apple VGA    adapter; 576p and 480p with Apple component AV cable; 576i and 480i    with Apple composite AV cable (cables sold separately)-   Video formats supported: H.264 video up to1080p, 30 frames per    second, main profile Level 3.1 with AAC-LC audio up to 160 Kbps, 48    kHz, stereo audio in .m4v, .mp4, and .mov file formats; MPEG-4 video    up to 2.5 Mbps, 640 by 480 pixels, 30 frames per second, simple    profile with AAC-LC audio up to 160 Kbps per channel, 48 kHz, stereo    audio in .m4v, .mp4, and .mov file formats; motion JPEG (M-JPEG) up    to 35 Mbps, 1280 by 1020 pixels, 30 frames per second, audio in    ulaw, PCM stereo audio in .avi file format:-   Three-axis gyro-   Accelerometer-   Proximity sensor-   Ambient light sensor-   etcetera.

Embodiments of the present disclosure may be used with other electronicdevices. Examples of suitable electronic devices include a portableelectronic device such as a media player, a cellular phone, a personaldata organizer, or the like. In such embodiments, a portable electronicdevice may include a combination of the functionalities of such devices.In addition, an electronic device may allow a user to connect to andcommunicate through the Internet or through other networks such as localor wide area networks. For example, a portable electronic device mayallow a user to access the interne and to communicate using e-mail, textmessaging, instant messaging, or using other forms of electroniccommunication. By way of example, the electronic device may be similarto an iPod having a display screen or an iPhone available from AppleInc.

In certain embodiments, a device may be powered by one or morerechargeable and/or replaceable batteries. Such embodiments may behighly portable, allowing a user to carry the electronic device whiletraveling, working, exercising, and so forth. In this manner, anddepending on the functionalities provided by the electronic device, auser may listen to music, play games or video, record video or takepictures, place and receive telephone calls, communicate with others,control other devices (e.g., via remote control and/or Bluetoothfunctionality), and so forth while moving freely with the device. Inaddition, the device may be sized such that it fits relatively easilyinto a pocket or the hand of the user. While certain embodiments of thepresent disclosure are described with respect to portable electronicdevices, it should be noted that the presently disclosed techniques maybe applicable to a wide array of other, less portable, electronicdevices and systems that are configured to render graphical data such asa desktop computer.

As shown, FIG. 8H includes a system diagram with a smart phone thatincludes an LED according to an embodiment of the present disclosure.The smart phone 8H06 is configured to communicate with a server 8H02 inelectronic communication with any forms of handheld electronic devices.Illustrative examples of such handheld electronic devices can includefunctional components such as a processor 8H08, memory 8H10, graphicsaccelerator 8H12, accelerometer 8H14, communications interface 8H11(possibly including an antenna 8H16), compass 8H18, GPS chip 8H20,display screen 8H22, and an input device 8H24. Each device is notlimited to the illustrated components. The components may be hardware,software or a combination of both.

In some examples, instructions can be input to the handheld electronicdevice through an input device 8H24 that instructs the processor 8H08 toexecute functions in an electronic imaging application. One potentialinstruction can be to generate an abstract of a captured image of aportion of a human user. In that case the processor 8H08 instructs thecommunications interface 8H11 to communicate with the server 8H02 (e.g.,possibly through or using a cloud 8H04) and transfer data (e.g., imagedata). The data is transferred by the communications interface 8H11 andeither processed by the processor 8H08 immediately after image captureor stored in memory 8H10 for later use, or both. The processor 8H08 alsoreceives information regarding the display screen's attributes, and cancalculate the orientation of the device, e.g., using information from anaccelerometer 8H14 and/or other external data such as compass headingsfrom a compass 8H18, or GPS location from a GPS chip 8H20, and theprocessor then uses the information to determine an orientation in whichto display the image depending upon the example.

The captured image can be rendered by the processor 8H08, by a graphicsaccelerator 8H12, or by a combination of the two. In some embodiments,the processor can be the graphics accelerator 8H12. The image can firstbe stored in memory 8H10 or, if available, the memory can be directlyassociated with the graphics accelerator 8H12. The methods describedherein can be implemented by the processor 8H08, the graphicsaccelerator 8H12, or a combination of the two to create the image andrelated abstract. An image or abstract can be displayed on the displayscreen 8H22.

FIG. 81 depicts an interconnection of components in an electronic device8100. Examples of electronic devices include an enclosure or housing, adisplay, user input structures, and input/output connectors in additionto the aforementioned interconnection of components. The enclosure maybe formed from plastic, metal, composite materials, or other suitablematerials, or any combination thereof. The enclosure may protect theinterior components of the electronic device from physical damage, andmay also shield the interior components from electromagneticinterference (EMI).

The display may be a liquid crystal display (LCD), a light-emittingdiode (LED) based display, an organic light-emitting diode (OLED) baseddisplay, or some other suitable display. In accordance with certainembodiments of the present disclosure, the display may display a userinterface and various other images such as logos, avatars, photos, albumart, and the like. Additionally, in certain embodiments, a display mayinclude a touch screen through which a user may interact with the userinterface. The display may also include various functions and/or systemindicators to provide feedback to a user such as power status, callstatus, memory status, or the like. These indicators may be incorporatedinto the user interface displayed on the display.

In certain embodiments, one or more of the user input structures can beconfigured to control the device such as by controlling a mode ofoperation, an output level, an output type, etc. For instance, the userinput structures may include a button to turn the device on or offFurther, the user input structures may allow a user to interact with theuser interface on the display. Embodiments of the portable electronicdevice may include any number of user input structures includingbuttons, switches, a control pad, a scroll wheel, or any other suitableinput structures. The user input structures may work with the userinterface displayed on the device to control functions of the deviceand/or any interfaces or devices connected to or used by the device. Forexample, the user input structures may allow a user to navigate adisplayed user interface or to return such a displayed user interface toa default or home screen.

Certain device may also include various input and output ports to allowconnection of additional devices. For example, a port may be a headphonejack that provides for the connection of headphones. Additionally, aport may have both input and output capabilities to provide for theconnection of a headset (e.g., a headphone and microphone combination).Embodiments of the present disclosure may include any number of inputand/or output ports such as headphone and headset jacks, universalserial bus (USB) ports, IEEE-1394 ports, and AC and/or DC powerconnectors. Further, a device may use the input and output ports toconnect to and send or receive data with any other device such as otherportable electronic devices, personal computers, printers, or the like.For example, in one embodiment, the device may connect to a personalcomputer via an IEEE-1394 connection to send and receive data files suchas media files.

The depiction of an electronic device 8100 encompasses a smart phonesystem diagram according to an embodiment of the present disclosure. Thedepiction of an electronic device 8100 illustrates computer hardware,software, and firmware that can be used to implement the disclosuresabove. The shown system includes a processor 8126, which isrepresentative of any number of physically and/or logically distinctresources capable of executing software, firmware, and hardwareconfigured to perform identified computations. A processor 8126communicates with a chipset 8128 that can control input to and outputfrom processor 8126. In this example, chipset 8128 outputs informationto display screen 8142 and can read and write information tonon-volatile storage 8144, which can include magnetic media and solidstate media, and/or other non-transitory media, for example. Chipset8128 can also read data from and write data to RAM 8146. A bridge 8132for interfacing with a variety of user interface components can beprovided for interfacing with chipset 8128. Such user interfacecomponents can include a keyboard 8134, a microphone 8136,touch-detection-and-processing circuitry 8138, a pointing device 8140such as a mouse, and so on. In general, inputs to the system can comefrom any of a variety of machine-generated and/or human-generatedsources.

Chipset 8128 also can interface with one or more data network interfaces8130 that can have different physical interfaces. Such data networkinterfaces 8130 can include interfaces for wired and wireless local areanetworks, for broadband wireless networks, as well as personal areanetworks. Some applications of the methods for generating, displayingand using the GUI disclosed herein can include receiving data over aphysical interface 8131 or be generated by the machine itself by aprocessor 8126 analyzing data stored in non-volatile storage 8144 and/orin memory or RAM 8146. Further, the machine can receive inputs from auser via devices such as a keyboard 8134, microphone 8136,touch-detection-and-processing circuitry 8138, and pointing device 8140and execute appropriate functions such as browsing functions byinterpreting these inputs using processor 8126.

1. (canceled)
 2. An optoelectronic semiconductor device having a contactprepared by the method comprising: depositing a metallic stack on asemiconductor surface of said optoelectronic semiconductor device; andwherein said metallic stack comprises at least layers of silver andplatinum, wherein, in said metallic stack, a silver layer does notcontact a platinum layer.
 3. The optoelectronic semiconductor device ofclaim 2, wherein said metallic stack also comprises one or more layersof at least one of Al, Au, Pd, Ni, Ge, Ti or Ru
 4. The optoelectronicsemiconductor device of claim 3, wherein said metallic stack comprises ametal scheme of Ti—Pt—Au—Pt.
 5. The optoelectronic semiconductor deviceof claim 2, wherein an interface is defined between said stack and saidsemiconductor surface and wherein said method further comprises,introducing a dose of oxygen into said metallic stack; and diffusing aportion of said oxygen though said metallic stack to said interface. 6.The optoelectronic semiconductor device of claim 5, wherein saidmetallic stack comprises a silver layer in contact with saidsemiconductor surface.
 7. The optoelectronic semiconductor device ofclaim 6, wherein said metallic stack comprises an oxygen-getteringmetal.
 8. The optoelectronic semiconductor device of claim 7, whereindiffusing comprises annealing the optoelectronic semiconductor device todiffuse an oxygen-gettering metal to said interface.
 9. Theoptoelectronic semiconductor device of claim 7, wherein saidoxygen-gettering metal comprises at least one of Ni, Al, Ti, Mg, or Sc.10. The optoelectronic semiconductor device of claim 7, wherein saiddiffusing comprises diffusing a portion of said oxygen-gettering metalto said interface, and diffusing a portion of said oxygen to saidinterface.